利用远红外激光干涉仪对Tokamak内部电子数密度和磁场分布进行测量是控制其放电状态的重要依据。从该方法的测量原理出发,分析了中频信号频率不稳定性对电子数密度和磁场分布测量以及Tokamak放电状态实时控制的影响;针对如何提高中频频...利用远红外激光干涉仪对Tokamak内部电子数密度和磁场分布进行测量是控制其放电状态的重要依据。从该方法的测量原理出发,分析了中频信号频率不稳定性对电子数密度和磁场分布测量以及Tokamak放电状态实时控制的影响;针对如何提高中频频率的稳定性提出了一套以单片机为核心的控制方案和控制系统,并研制了稳频控制器;通过现场调试,对比分析了控制前后中频信号的频率变化。实验结果表明,未接入稳频控制器时,30 min内中频频率中心值变化了90 k Hz;而接入稳频控制器后,中频频率中心值始终在设定值的±5 k Hz范围内变化。这表明该控制方法和控制系统能够实现中频频率的稳定控制。展开更多
The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLP...The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLPS-ITER program is employed to examine the effects of the magnetic field strength and neutral pressure in the device on the heat flux experienced by the target plate of the HIT-PSI device.The findings of the numerical simulation indicate a positive correlation between the magnetic field strength and the heat flux density.Conversely,there is a negative correlation observed between the heat flux density and the neutral pressure.When the magnetic field strength at the axis exceeds 1 tesla and the neutral pressure falls below 10 Pa,the HIT-PSI has the capability to attain a heat flux of 10 MW·m-2 at the target plate.The simulation results offer a valuable point of reference for subsequent experiments at HIT-PSI.展开更多
The attack angle may greatly affect the hypersonic plasma sheaths around the re-entry vehicle,thereby affecting the transmission characteristics of electromagnetic(EM)waves in the sheaths.In this paper,we propose an i...The attack angle may greatly affect the hypersonic plasma sheaths around the re-entry vehicle,thereby affecting the transmission characteristics of electromagnetic(EM)waves in the sheaths.In this paper,we propose an integrated three-dimensional(3D)model with various attack angles and realistic flying conditions of radio attenuation measurement C-II(RAM C-II)re-entry tasks for analyzing the effect of the attack angle on the transmission characteristics of EM waves in the sheaths.It is shown that the electron density and collision frequency of the sheath on the windward side can be increased by an order of magnitude with the increase of the attack angle.Meanwhile,the thickness of the sheath on the leeward side is increased where the electron density and collision frequency are reduced.The EM waves are mainly reflected on the windward plasma sheath due to the cutoff effect,and the radio-frequency(RF)blackout is mitigated if the antenna is positioned on the leeward side.Thus,by planning the trajectory properly and installing the antenna accordingly during the re-entry,it is possible to provide an approach for mitigation of the RF blackout problem to an extent.展开更多
文摘利用远红外激光干涉仪对Tokamak内部电子数密度和磁场分布进行测量是控制其放电状态的重要依据。从该方法的测量原理出发,分析了中频信号频率不稳定性对电子数密度和磁场分布测量以及Tokamak放电状态实时控制的影响;针对如何提高中频频率的稳定性提出了一套以单片机为核心的控制方案和控制系统,并研制了稳频控制器;通过现场调试,对比分析了控制前后中频信号的频率变化。实验结果表明,未接入稳频控制器时,30 min内中频频率中心值变化了90 k Hz;而接入稳频控制器后,中频频率中心值始终在设定值的±5 k Hz范围内变化。这表明该控制方法和控制系统能够实现中频频率的稳定控制。
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFE0303105)the Fundamental Research Funds for the Central Universities(Grant No.2022FRFK060021)the National MCF Energy Research and Development Program(Grant No.2019YFE03080300).
文摘The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLPS-ITER program is employed to examine the effects of the magnetic field strength and neutral pressure in the device on the heat flux experienced by the target plate of the HIT-PSI device.The findings of the numerical simulation indicate a positive correlation between the magnetic field strength and the heat flux density.Conversely,there is a negative correlation observed between the heat flux density and the neutral pressure.When the magnetic field strength at the axis exceeds 1 tesla and the neutral pressure falls below 10 Pa,the HIT-PSI has the capability to attain a heat flux of 10 MW·m-2 at the target plate.The simulation results offer a valuable point of reference for subsequent experiments at HIT-PSI.
基金supported by National Natural Science Foundation of China(Nos.92271202 and 92371105)。
文摘The attack angle may greatly affect the hypersonic plasma sheaths around the re-entry vehicle,thereby affecting the transmission characteristics of electromagnetic(EM)waves in the sheaths.In this paper,we propose an integrated three-dimensional(3D)model with various attack angles and realistic flying conditions of radio attenuation measurement C-II(RAM C-II)re-entry tasks for analyzing the effect of the attack angle on the transmission characteristics of EM waves in the sheaths.It is shown that the electron density and collision frequency of the sheath on the windward side can be increased by an order of magnitude with the increase of the attack angle.Meanwhile,the thickness of the sheath on the leeward side is increased where the electron density and collision frequency are reduced.The EM waves are mainly reflected on the windward plasma sheath due to the cutoff effect,and the radio-frequency(RF)blackout is mitigated if the antenna is positioned on the leeward side.Thus,by planning the trajectory properly and installing the antenna accordingly during the re-entry,it is possible to provide an approach for mitigation of the RF blackout problem to an extent.
